Major histocompatibility complex class II HLA-DR (HLA-DR) (HLA-DR)

Major histocompatibility complex class II HLA-DR (HLA-DR) is a heterodimeric cell surface receptor primarily expressed on professional antigen-presenting cells, including B cells, macrophages, and dendritic cells (UniProt P01903). Its fundamental biological role involves the presentation of exogenous peptides to CD4+ T-helper cells, a process essential for the initiation and regulation of the adaptive immune response (StatPearls, MHC Class II). HLA-DR is critically involved in the pathogenesis of various autoimmune diseases, such as rheumatoid arthritis and multiple sclerosis, where specific HLA-DR alleles are linked to the presentation of self-antigens (PubMed, PMID: 25135300). In the context of oncology, HLA-DR is frequently expressed on the surface of B-cell lymphomas and leukemias, serving as a target for monoclonal antibodies that induce cell death through apoptosis or immune-mediated mechanisms (PubMed, PMID: 16123218). Additionally, the expression levels of HLA-DR on monocytes (mHLA-DR) serve as a vital biomarker for assessing immune competence in patients with sepsis or major trauma (PubMed, PMID: 21336177). Therapeutic interventions targeting HLA-DR include peptide-based drugs that compete for the binding groove and antibodies designed to deplete malignant cells or modulate immune signaling (DrugBank, DB00043).

Other names

Human leukocyte antigen DRMHC class II DRHLA-DRB1/DRA complexMHC II DR

Competitive inhibition of the peptide-binding groove to prevent autoantigen presentation and direct induction of apoptosis or antibody-dependent cellular cytotoxicity in HLA-DR-positive cells (PubMed, PMID: 16123218; FDA Label).